However, a shortage of cash could cause the police to take an interest, as they can confisate a brothel-keeper's assets via POCA. There was even one case where a WG had to take time off due to illness, and allowed another WG to use her home for awhile: the police raided it and took everything of value (including her dead mother's jewelry), because she couldn't prove that it hadn't been bought with proceeds from "organised crime".
Some police are utter cunts.
Not all of them though, which could explain why no punter appears to have been prosecuted under the "coercion" law. Hard to say if that's because the police are more interested in the pimp than the punters, or whether it's because outright coercion is rare. The police don't have to prove that the punter knew the WG was coerced, but presumably they still have to prove that she WAS coerced.
The recent Parliamentary inquiry recommended an immediate "cease and desist" on the persecution of well-run brothels, but this doesn't seem to have been taken onboard yet.